be added or subtracted only in lumps of size e. For this reason we say that charge is
quantized. To remind us of the quantized nature of electric charge, the charge of a
particle (or object) is denoted by the letter q. In the SI system of units, charge is
expressed in coulombs (abbreviated C). One coulomb is a tremendous amount of
charge; the value of e is about 1.6 × 10−19 C.
Elementary,
My Dear Watson
The elementary charge is
equal to the magnitude of
the charge of an
electron or proton.